Many computer programs currently exist for manipulating digitized audio data. The computer programs provide a user with the ability to play and edit the audio data. For example, musical editing computer programs can be used to combine data from various musical compositions into new musical compositions. Standard data formats for audio data have been developed to facilitate the sharing of audio data among various computer programs.
One such standard format audio data is the Resource Interchange File Format (RIFF). FIG. 1 illustrates the RIFF format. The RIFF format includes a header 101 and audio data 102. The header includes information identifying the file as being in the RIFF format (i.e., the characters RIFF); the length of the file; the file type (e.g., WAVE); the encoding format of the audio data (e.g., 1 for pulse code modulation); the number of channels used to store the audio data (e.g., 2 for stereo); the sampling rate of the raw audio data (e.g., 44100 Hz); the average number of bytes that correspond to one second of audio data (e.g., 176400); the average number of bytes in each sample (e.g., 4); the number of bits used per sample (e.g., 16); and the number of bytes of raw audio data. The header is followed by the audio data stored at the fidelity level specified by the header. The fidelity level is characterized by the number of channels (stereo/mono), the number of bits per sample, and the sampling rate. In the example of FIG. 1, the fidelity level specified is characterized as in stereo with 16 bit samples and a sampling rate of 44100 Hz.
The music industry is currently publishing many musical compositions on CD ROMs. A CD ROM typically contains a track for each musical composition recorded. A standard format that is different from the RIFF format has been defined for the recording of CD ROMs. According to this standard CD ROM format, the audio data on a CD ROM is recorded at a fidelity level that is known as the "original fidelity level."
Unfortunately, existing computer programs typically cannot access audio data that is stored in standard CD ROM format. These computer programs can typically only access audio data that is stored in the standard format for audio data, such as the RIFF format. One approach to allow a computer program to access audio data in CD ROM format would be to copy the audio data and store it in the RIFF format. However, such a copy would typically be a very large file that uses a considerable amount of disk space. Also, these computer programs often need to access audio data at various fidelity levels. However, multiple copies of the audio data at various fidelity levels would use vast amounts of disk space.